Biology Reference
In-Depth Information
301
Pyrrhalta viburni
(Paykull) (
301-303
)
Viburnum beetle
Generally common on wild guelder-rose (
Viburnum
opulus
); also a pest of ornamental
Viburnum.
Widespread in central and northern Europe.
DESCRIPTION
Adult:
4.5-6.5 mm long; yellowish brown to light
brown; elytra elongate, parallel-sided and regularly
rounded posteriorly; body coated with a short, silky
pubescence; antennae relatively long, particularly in the
male.
Egg:
0.4 mm across; rounded, dark yellow to
brownish.
Larva:
up to 9 mm long; shiny greenish
yellow to whitish, with numerous black pinacula and
plates; body distinctly swollen, particularly posteriorly.
301
Viburnum beetle (
Pyrrhalta viburni
).
LIFE HISTORY
Overwintered eggs hatch in May. The larvae then feed
voraciously on the expanded leaves, becoming fully
grown in 4-5 weeks. They then enter the soil to pupate
in earthen cells some 30-50 cm below the surface.
Adults appear about ten days later, usually in July. After
mating, the females, which may survive until September
or October, deposit eggs in the tips of one-year-old
shoots. Each female is capable of depositing several
hundred eggs, and infested bushes are commonly
attacked by large numbers of larvae. There is just one
generation annually.
302
DAMAGE
Larvae cause considerable damage; they bite out
irregular holes in the leaf blades, between the major
veins, much of the remaining tissue eventually turning
brown. Such depredations are often extensive, affecting
both the appearance and vigour of infested plants.
302
Larva of viburnum beetle (
Pyrrhalta viburni
).
303
303
Viburnum beetle (
Pyrrhalta viburni
) damage to foliage of
Viburnum
.
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